This application relates to medical x-ray positioners and in particular to a positioner using independently articulated arms to support the x-ray source and x-ray detector.
Conventional x-ray positioners provide mechanical supports to hold an x-ray source and x-ray detector in opposition about a patient for a limited number of specific procedures. For procedures in which the patient is standing, the x-ray source may be attached to a pillar allowing adjustment in its height as directed toward an x-ray detector attached to an opposing wall or a second similar pillar. For procedures in which the patient is supine, the x-ray source and detector may be attached to opposite sides of a patient table. Alternatively the x-ray source and the detector may be attached to opposite ends of a C-arm which is supported by a sliding collar allowing the angle of the x-rays through the patient to be varied.
Multi-axis robotic arms, positioned above and below the patient table, have been proposed to provide support for the x-ray source and x-ray detector such as may reduce interference between the support structure and other equipment and personnel. See, for example, U.S. Pat. No. 6,200,024 to Negrelli citing U.S. Pat. No. 4,894,855 to Kresse.
Such systems require complex multi-axis movement for simple adjustments of the x-ray tube and detector in angulation or translation, and appear to have limited utility for certain common x-ray procedures such as those requiring the patient to stand. Further such systems make it difficult or impossible to swap the location of the x-ray source from beneath the patient to above the patient, when the patient is supine, and an improved image might thereby be obtained.
The present invention provides a simplified mechanism for independently supporting an x-ray tube and detector for greater positioning flexibility yet providing simplified axis motion for typical repositioning actions. Generally the invention provides two independently articulated arms holding the x-ray tube and detector, respectively, where both arms mounted to a common supporting surface offset to one side of the patient. The arms present a fully variable C-shaped structure, avoiding the invariable bulk of a fixed C-arm, while still providing a simple and intuitive structure for holding the x-ray tube and x-ray detector in opposition. The offset mounting of the arms provides a greater range of positioning than may be obtained when the arms are mounted above and below a patient table. Mounting the arms on a common side of the patient reduces the number of axes required for flexible repositioning, allowing some axes to be implemented in common to reduce the systems mechanical complexity and improve performance.